scraph

I just installed a Transgo shift kit for the 4R70W in a 2003 Mustang GT. When shifting into R with the transmission fluids cold, the engine will immediatelly stall. There is no shuddering or struggle, it almost seems like the engine was killed. When shifting into 2nd the idle will bog down (~500) and attempt to recover by overrevving (~1100) followed by another cycle or two of the same and an eventual stall. The transmission will shift into 1st just fine when everything is cold. Further, the vehicle can be driven from 1st and manually shifted into 2nd while moving with no apparent issues (other than the hard shift from the kit).

I am wondering whether these are symptoms of low fluid as they go away after the transmission fluid has warmed up (and expanded)? The fluid level does indicate on the stick while running in park but I'm not very trusting of this indication as on one side of the indicator there is a continuous line of fluid (possibly picked up on its way down the filler tube). Any opinions? Thanks!

scraph

bump

97targa

In order to check the fluid the car must be at operating temp and in either park or nuetral. Doesn't really matter. The kit will def. shift your car harder when it's cold than when it's warmed up.
What kind of fluid did you use?
Did you replace the filter/screen? Maybe it's not seated in all the way causing fluid to leak at pick-up tube.

scraph

Might have dropped the ball on the filter replacement element. The orange rubber seal on the filter cam off into the receiver in the transmission so I took it off of the replacement filter and jammed the new filter into the old seal while installed. It seemed to seat well enough but since you mentioned that, it may not have. The fluid we used was I believe Castrol ... the Mercon V High Mileage variant. I will try reseating the filter, properly this time.